Some mobile phones are capable of operating under multiple communications standards, such as digital and analog, multiple digital standards (e.g., CDMA and GSM), etc. Communication standards have also been developed to theoretically allow cellular phones to communicate with a traditional cellular network as well as an Unlicensed Mobile Access Network. Dual mode devices or handsets capable of communicating with these two dissimilar networks are inefficient and cumbersome because each mode requires its own communications interfaces and applications.
For example, FIG. 1 shows a block diagram of the hardware/software elements of a cellular/UMA dual mode device 100 in accordance with the prior art. The cellular/UMA dual mode device 100 uses two distinct communications subsystems (Voice Over Internet Protocol (VoIP) 102 and Cellular Radio Frequency (RF) (e.g., GSM) 104) operated by a common operating system 106 to communicate with the two different communications networks (e.g., UMA and GSM). The handset 100 UMA subsystem 102 includes a wireless local area network (WLAN) transceiver 108, a network adapter 110, a VoIP protocol stack 112, a VoIP communications interface 114 and Internet Protocol (IP) based applications 116 (e.g., Phone Book 118, VoIP Client 120, Internet Browser 122, E-mail 124, etc.). The handset 100 Cellular subsystem 104 includes a RF transceiver 126, a baseband processor 128, a cellular protocol stack 130, a cellular interface 132 and cellular-based applications 134 (e.g., Phone Book 136, SMS 138, MMS 140, E-mail 142, etc.).
The two distinct subsystems are a result of the fact that wireless computer network communications have been developed separately and in parallel with cellular communications. As a result, IP-based applications 116 and cellular-based applications 134 have been developed independently of one another and are not capable of working across platforms without significant customization and modification. In other words, an “off-the-shelf” IP-based Phone Book application 118 cannot interface with the cellular interface 132. Likewise, and “off-the-shelf” cellular based Phone Book application 136 cannot interface with the VoIP communications interface 114. As shown in FIG. 1, the current solution to this problem is to have a separate and distinct subsystem with its own applications for each communications mode.
Another problem is that a traditional battery for a cellular/UMA dual mode device may only last for less than 24 hours under normal use before it must be recharged. For example, a typical GSM phone will operate in three power modes: active (connected to network during an active session); sleep (connected to the network in standby mode); and deep sleep (not connected to the network). Typical power consumption for these three power modes can be: 150 mA in active mode; 1 mA in sleep mode; and 0.2 mA in deep sleep mode. As will be appreciated by those skilled in the art, power consumption of a dual mode phone can easily be twice that of a single mode phone. As a result, the battery life and corresponding talk times and standby times are cut in half. Consumers have grown accustomed to the current talk and standby times of single mode phones, so the shortened talk and standby times of a dual mode phone are undesirable.
In addition, although establishing communication connections and sessions within a cellular network are virtually seamless to the end user, establishing communication connections and sessions to an UMAN are currently far from seamless. If a user has difficulty connecting to the UMAN, the user must figure out the problem on his/her own or consult the operator of the UMAN. As a result, the user will likely become frustrated and dissatisfied with the dual mode communications device. Accordingly, the user may not continue to use the dual mode device or may influence others not to use dual mode devices because of his/her bad experience.
There is, therefore, a need for a method and apparatus for a dual mode mobile device that can use both cellular-based and IP-based applications without having separate and distinct subsystems for each communications mode.